body {
    height: 100vh;
    background-color: #545454;
    display: flex;
    justify-content: center;
    align-items: center;
}

button {
    margin: 20px;
    padding: 15px 25px;
    border: 0;
    border-radius: 10px;
    color: white;
    font-size: 20px;
    line-height: 1em;
    cursor: pointer;
}

button:active {
    margin-top: 10px;
}

button.green {
    background: linear-gradient(-45deg, #9ccc65 50%, #699833 60%, #9ccc65 70%);
    background-size: 600% 100%;
    animation: shine 15s linear infinite;
}

button.blue {
    background: linear-gradient(-45deg, #69bbef 40%, #1e14a5 50%, #346ad6 60%);
    background-size: 600% 100%;
    animation: shine 15s linear infinite;
}

@keyframes shine {
    0% {
        background-position-x: 400%;
    }

    50% {
        background-position-x: 0%;
    }

    100% {
        background-position-x: -400%;
    }
}